Somatic genes required for post-meiotic spermatogenesis

描述（由申请人提供）：由于精子发生的机制在所有动物门中都是保守的，因此对人类男性不育原因的认识可能来自对模式生物的研究。在果蝇减数分裂后的精子发生过程中，一个由64个单倍体精子细胞核组成的包囊成熟为一束由64个成熟精子组成的有组织的束。这个成熟过程，包括核成形和伸长，轴丝的构建，以及精子细胞的个体化，其中每个伸长的精子细胞都被包裹在自己的质膜内，发生在由两个体细胞囊细胞组成的生精囊肿内。虽然这两个囊细胞已被证明在早期精子发生过程中发挥关键的信号作用，它们在减数分裂后精子发生过程中的作用仍然没有得到表征。这项工作旨在揭示精子减数分裂后成熟所需的体细胞囊细胞基因。使用P-元件增强子检测线和GFP标记的蛋白质陷阱，在后期精子发生过程中在包囊细胞中表达的基因将被分离。随后，通过从候选插入物中分离相邻的遗传单元来发现相应的基因，并获得突变。在互补方法中，适当表达的基因中的新突变将通过P元件动员产生。将使用光学显微镜筛选新获得的突变体的晚期生精缺陷。表型上感兴趣的突变将使用已知的分子标记和落射荧光显微镜进一步表征。将对减数分裂后精子发生的候选体细胞调节因子进行测序，并在其他物种中鉴定相关基因。由于昆虫和哺乳动物精子发生的功能相似，鉴定果蝇精子细胞成熟的体细胞调节因子可能有助于揭示哺乳动物睾丸中支持细胞和生殖细胞之间的相互作用，从而深入了解哺乳动物精子细胞形态发生的体细胞调节，并最终了解人类男性生育力的机制。

DESCRIPTION (provided by applicant): Since the mechanisms of spermatogenesis are conserved across all animal phyla, insights into the causes of human male infertility may come from studies in model organisms. During post-meiotic spermatogenesis in Drosophila, a cyst of 64 haploid spermatid nuclei is matured into an organized bundle of 64 mature spermatozoa. This maturation process, which includes nuclear shaping and elongation, construction of the axoneme, and spermatid individualization, in which each elongated spermatid is invested within its own plasma membrane, occurs within a spermatogenic cyst comprised of two somatic cyst cells. While these two cyst cells have been shown to play critical signaling roles during early spermatogenesis, their roles during post-meiotic spermatogenesis remain uncharacterized. This work seeks to uncover genes required in the somatic cyst cells for the post-meiotic maturation of spermatozoa. Using both P-element enhancer-detector lines and GFP-tagged protein traps, genes expressed in the cyst cells during late-stage spermatogenesis will be isolated. Subsequently, the corresponding genes will be uncovered by isolating neighboring genetic units from candidate insertions and mutations will be obtained. In a complimentary approach, novel mutations in appropriately expressed genes will be generated by P-element mobilization. Newly obtained mutants will be screened for late-stage spermatogenic defects using light microscopy. Phenotypically interesting mutations will be further characterized using known molecular markers and epi-flourescence microscopy. Candidate somatic regulators of post-meiotic spermatogenesis will be sequenced and related genes will be identified in other species. Since insect and mammalian spermatogenesis are functionally similar, identification of somatic regulators of spermatid maturation in Drosophila may help uncover interactions between the somatic Sertoli cells and the germline in the mammalian testis, thus providing insight into somatic regulation of mammalian spermatid morphogenesis, and ultimately, into the mechanisms governing human male fertility.